Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Elevated temperatures can be detrimental to a performance of many electronic circuits (e.g., image sensors) because of effects on leakage currents, thermal noise, and device mismatch conditions. Image sensors include a detector array comprising pixel circuitry, and additional circuitry laid out on a substrate around the detector array. The detector array is usually more sensitive to temperature increases which affect performance of the detector array (e.g., temperature increases can cause increased leakage currents resulting in false image signal and degraded images).
Thermal management of image sensors and other integrated circuits has focused on removing heat from the entire image sensor. Such thermal management techniques can increase an amount of power required to remove heat due to heat dissipated by all circuits of the die. With small devices or handheld mobile devices, active cooling of image sensors can be problematic due to an amount of power to perform the thermal management techniques and constraints on power available in the mobile device. For example, transferring heat from the entire image sensor could require a few Watts or more of power in the system, which may not be available. This additional power may also cause excessive heating of the mobile device, which may not be acceptable.
In addition, cooling of image sensors in larger imaging devices has been performed using additional components. However, additional components can add to power requirements, as well as increase space requirements, which may not be acceptable in space-constrained systems, such as mobile devices. Imagers in mobile devices have been typically only passively cooled, and efficiency of this solution may be limited due to an adverse operating environment and severe constraints inside a mobile device.